With the development of the display technology, flat display devices, such as liquid crystal display (LCD), organic light emitting diode (OLED) display, have become the mainstream display devices because of the advantages such as high display quality, power saving, thin profile, wide application, and so on. At present, in the manufacturing process of a display panel, every stage (e.g., production stage, testing stage or the like) needs a mechanical arm to move a plate-like object, such as a glass substrate, a display master plate or a separated display panel, between different bases, between a base and a transmission device or between different transmission devices, that is, the mechanical arm is needed to pick up the plate-like object from a base or a transmission device or put down the plate-like object on the base or the transmission device. In the process of picking up or putting down the plate-like object, when there occurs a relative position offset between the plate-like object and the base or the transmission device, the plate-like object may collide with the base or the two side edges of the transmission device, resulting in breakage of the plate-like object, increasing the rejection rate and reducing the production capacity.